A vane device for a wind turbine apparatus, as disclosed in Taiwanese Patent No. M485960, includes a rotary shaft, and a plurality of vane units connected to the rotary shaft and angularly spaced apart from each other. Each vane unit includes a grid frame connected to the rotary shaft, a plurality of vanes swingably connected to the grid frame, and a plurality of counterweight members each of which is disposed on one end of a respective one of the vanes. When one of the vane units is in the upwind position, the vanes of the one of the vane unit are in a cover position to generate a rotational torque. Meanwhile, the other vane units are in the downwind position and the vanes thereof are in an open position, thereby generating a reverse rotational torque. By virtue of the structural arrangement of the vane device, the rotational torque is greater than the reverse rotational torque, thereby enhancing use efficiency of wind power.
Because the vane device is exposed to sunlight and outdoor weathering conditions, the vanes are easily damaged so that it is inevitable that the damaged vane and the counterweight member will fall or the counterweight member itself will drop from the damaged vane to cause injury to the people passing by. Hence, the aforesaid vane device is not safe to use.